Field of the Invention
The present invention relates to a processing apparatus, a control method thereof, and a non-transitory computer readable medium. The present invention relates to a technique of outputting compressed data to a processing unit which performs conversion processing of decompressing compressed data and converting the decompressed data into data for printing.
Description of the Related Art
Some printers can obtain, as print data, compressed image data which has undergone compression processing by an image compression technique such as JPEG in an apparatus, or from a memory card or a network. The printers decompress the obtained compressed image data, and then perform various types of processing such as color conversion into a CMYK color space, error diffusion of converting the data into a form that can be output by a print engine, and quantization like dithering, thereby printing an image on a recording medium.
In Japanese Patent Laid-Open No. 9-6952, interconversion between an RGB color space and a YCbCr color space is performed in JPEG compression/decompression processing. At this time, Japanese Patent Laid-Open No. 9-6952 has disclosed a method of preventing, by setting the number of bits in halfway calculation larger than the original number of bits of processing target image data, errors from being accumulated even if color space conversion processing operations by integer computing are repeated over and over.
This method is useful in obtaining as high as possible accuracy of decompression output and also in performing decompression processing only once without repeating compression/decompression operations.
However, if the number of bits to be used for image data calculation is set larger than the primary original number of bits of that image data, an unintended pixel value may be reproduced depending on those processing contents. Therefore, if such processing is directly implemented in each printer, an unintended image is formed on the recording medium or a printing operation is performed on image data which need not originally undergo the printing operation. This may cause wasteful consumption of a recording material used for printing and a decrease in throughput.